//
// (C) Copyright 2009 Irantha Suwandarathna (irantha@gmail.com)
// All rights reserved.
//

/* Copyright (c) 1995-2000, The Hypersonic SQL Group.
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the Hypersonic SQL Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE HYPERSONIC SQL GROUP,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * on behalf of the Hypersonic SQL Group.
 *
 *
 * For work added by the HSQL Development Group:
 *
 * Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


using System;
using EffiProzDB.RowIO;
using EffiProzDB.Lib;

namespace EffiProzDB
{

    // fredt@users 20020221 - patch 513005 by sqlbob@users (RMP)
    // fredt@users 20020920 - patch 1.7.1 - refactoring to cut memory footprint
    // fredt@users 20021205 - patch 1.7.2 - enhancements
    // fredt@users 20021215 - doc 1.7.2 - javadoc comments
    // boucherb@users - 20040411 - doc 1.7.2 - javadoc comments

    /**
     *  In-memory representation of a disk-based database row object with  methods
     *  for serialization and de-serialization. <p>
     *
     *  A CachedRow is normally part of a circular double linked list which
     *  contains all of the Rows currently _in the Cache for the database. It is
     *  unlinked from this list when it is freed from the Cache to make way for
     *  other rows.
     *
     *  New class from the Hypersonic Original
     *
     * @author Thomas Mueller (Hypersonic SQL Group)
     * @version    1.7.2
     * @since Hypersonic SQL
     */
    public class CachedRow : Row
    {

        public const int NO_POS = -1;

        //
        protected Table tTable;
        public int storageSize;

        /**
         *  Flag indicating unwritten data.
         */
        protected bool hasDataChanged;

        /**
         *  Flag indicating Node data has changed.
         */
        bool hasNodesChanged;

        /**
         *  Default constructor used only _in subclasses.
         */
        public CachedRow() { }

        public static CachedRow newCachedRow(Table t,
                                             Object[] o)
        {

            if (t.isText())
            {
                return new CachedDataRow(t, o);
            }
            else
            {
                return new CachedRow(t, o);
            }
        }

        /**
         *  Constructor for new Rows.  Variable hasDataChanged is set to true in
         *  order to indicate the data needs saving.
         *
         * @param t table
         * @param o row data
         * @  if a database access error occurs
         */
        public CachedRow(Table t, Object[] o)
        {

            tTable = t;

            int indexcount = t.getIndexCount();

            nPrimaryNode = Node.newNode(this, 0, t);

            Node n = nPrimaryNode;

            for (int i = 1; i < indexcount; i++)
            {
                n.nNext = Node.newNode(this, i, t);
                n = n.nNext;
            }

            oData = o;
            hasDataChanged = hasNodesChanged = true;
        }

        /**
         *  Constructor when read from the disk into the Cache.
         *
         * @param t table
         * @param _in data source
         * @ 
         * @ 
         */
        public CachedRow(Table t,
                         RowInputInterface _in)  {

        tTable      = t;
        iPos        = _in.getPos();
        storageSize = _in.getSize();

        int indexcount = t.getIndexCount();

        nPrimaryNode = Node.newNode(this, _in, 0, t);

        Node n = nPrimaryNode;

        for (int i = 1; i < indexcount; i++) {
            n.nNext = Node.newNode(this, _in, i, t);
            n       = n.nNext;
        }

        oData = _in.readData(tTable.getColumnTypes());
    }

        private void readRowInfo(RowInputInterface _in)
        {
            // for use when additional transaction info is attached to rows
        }

        /**
         *  This method is called only when the Row is deleted from the database
         *  table. The links with all the other objects apart from the data
         *  are removed.
         *
         * @ 
         */
        public override void delete()
        {

            base.delete();

            hasNodesChanged = hasDataChanged = false;
            tTable = null;
        }

        public override int getStorageSize()
        {
            return storageSize;
        }

        /**
         * Sets the file position for the row
         *
         * @param pos position _in data file
         */
        public override void setPos(int pos)
        {
            iPos = pos;
        }

        /**
         * Sets flag for Node data change.
         */
        public void setChanged()
        {
            hasNodesChanged = true;
        }

        /**
         * Returns true if Node data has changed.
         *
         * @return bool
         */
        public override bool hasChanged()
        {
            return hasNodesChanged;
        }

        /**
         * Returns the Table to which this Row belongs.
         *
         * @return Table
         */
        public Table getTable()
        {
            return tTable;
        }

        /**
         * returned size does not include the row size written at the beginning
         */
        public override int getRealSize(RowOutputInterface _out)
        {
            return tTable.getIndexCount() * DiskNode.SIZE_IN_BYTE
                   + _out.getSize(this);
        }

        public override void setStorageSize(int size)
        {
            storageSize = size;
        }

        /**
         * Returns true if any of the Nodes for this row is a root node.
         * Used only _in Cache.java to avoid removing the row from the cache.
         *
         * @return bool
         * @ 
         */
        public override bool isKeepInMemory()
        {
            lock (this)
            {
                Node n = nPrimaryNode;

                while (n != null)
                {
                    if (n.isRoot())
                    {
                        return true;
                    }

                    n = n.nNext;
                }

                return false;
            }
        }

        /**
         *  Using the internal reference to the Table, returns the current cached
         *  Row. Valid for deleted rows only before any subsequent insert or
         *  update on any cached table.<p>
         *
         *  Access to tables while performing the internal operations for an
         *  SQL statement result _in CachedRow objects to be cleared from the cache.
         *  This method returns the CachedRow, loading it to the cache if it is not
         *  there.
         * @return the current Row _in Cache for this Object
         * @ 
         */
        public override Row getUpdatedRow()
        {
            lock (this)
            {
                return tTable == null ? null
                                      : (CachedRow)tTable.rowStore.get(iPos);
            }
        }

        /**
         * used _in CachedDataRow
         */
        public virtual void setNewNodes() { }

        /**
         *  Used exclusively by Cache to save the row to disk. New implementation
         *  _in 1.7.2 writes _out only the Node data if the table row data has not
         *  changed. This situation accounts for the majority of invocations as
         *  for each row deleted or inserted, the Nodes for several other rows
         *  will change.
         *
         * @param output data source
         * @ 
         * @ 
         */
        public override void write(RowOutputInterface _out)
        {

            try
            {
                writeNodes(_out);

                if (hasDataChanged)
                {
                    _out.writeData(oData, tTable);
                    _out.writeEnd();

                    hasDataChanged = false;
                }
            }
            catch (Exception ) { }
        }

        private void writeRowInfo(RowOutputInterface _out)
        {

            // for use when additional transaction info is attached to rows
        }

        public override void write(RowOutputInterface _out, IntLookup lookup)
        {

            _out.writeSize(storageSize);

            Node rownode = nPrimaryNode;

            while (rownode != null)
            {
                ((DiskNode)rownode).writeTranslate(_out, lookup);

                rownode = rownode.nNext;
            }

            _out.writeData(getData(), getTable());
            _out.writeEnd();
        }

        /**
         *  Writes the Nodes, immediately after the row size.
         *
         * @param out
         *
         * @ 
         * @ 
         */
        private void writeNodes(RowOutputInterface _out)
        {

            _out.writeSize(storageSize);

            Node n = nPrimaryNode;

            while (n != null)
            {
                n.write(_out);

                n = n.nNext;
            }

            hasNodesChanged = false;
        }

        /**
         * With CACHED tables there may possibly exist two copies of the row.
         * All copies will have the same iPos.
         *
         * @param obj row to compare
         * @return bool
         */
        public override bool Equals(Object obj)
        {

            if (obj == this)
            {
                return true;
            }

            if (obj is CachedRow)
            {
                return ((CachedRow)obj).iPos == iPos;
            }

            return false;
        }

        /**
         * Hash code is valid only until a modification to the cache
         *
         * @return file position of row
         */
        public override int GetHashCode()
        {
            
            return iPos;
        }
    }
}
